1. Technical Field
The present invention relates to tablet computers in general, and in particular to a convertible tablet computer equipped with microphones, and more particularly, relates to a method for controlling processing of sound signals collected by the microphones on a tablet computer according to a use mode of the tablet computer.
2. Description of Related Art
Among personal computers (PCs), those having a thin size and allowing manipulations thereof with pen input on a display thereof are called tablet PCs. Tablet PCs can provide equivalent functions to notebook computers (laptop PC) while being operated with pen input without the usage of a keyboard. The tablet PCs come in two basic types: convertibles and pure tablets. The convertibles have a structure that allows a laptop PC equipped with a keyboard to be used as a tablet PC by changing a direction of a display of the laptop PC. The pure tablets have a structure that is not equipped with a keyboard and allows operations thereof with only pen input.
Among tablet PCs, there is one that converts user's sound signals collected by microphones into digital data and performs sound recognition thereon to be used for various purposes. Since sound input environment generally includes a source of noise, in order to obtain high sound recognition accuracy, it is necessary to separate or emphasize a target sound from or against noise. In this regard, there is a known technique called beamforming that collects sound with a set of microphones constituting a microphone array and emphasize a target sound by using a phase difference of sound signals received by the respective microphones based on a direction of a sound source and a distance between the microphones, thereby suppressing noise. The beamforming processes sound signals by increasing sensitivity to a target sound from a particular direction with respect to the microphone array while decreasing sensitivity to noise from other directions.
In convertible tablet PCs, the position of a user's mouth with respect to a microphone is different between a case of using the tablet PCs with keyboard input (i.e., PC use mode) and a case of using them with pen input (i.e., tablet use mode). Therefore, in some cases, even when the sensitive direction of beamforming is set so that the sound uttered from the user's mouth is emphasized in the PC use mode, the sound is not emphasized in the tablet use mode but suppressed. When it is unable to recognize the sound after the use mode is changed from the PC use mode to the tablet use mode, the user mistakenly attributes the inability to recognize the sound to a device failure. Although improved convenience can be provided because when the user stops the beamforming function, the tablet PC is able to utilize the sound that is not emphasized and thus has noise mixed therein; manipulating the beamforming function every changing of the use mode involves complication.